Evaporator and fuel reformer having the same

ABSTRACT

An evaporator (e.g., a small-sized high-efficiency evaporator) and a fuel reformer having the same. The evaporator has multi-stage structure (e.g., a four-stage disk structure), in which the respective disks are filled with fin structures. The first two disks through which exhaust gas passes and the second two disks through which water passes are stacked alternately with each other. Also, the first two disks are coupled with each other by a first pipe penetrating through one of the second two disks, and the second two disks are coupled with each other by a second pipe penetrating through one of the first two disks.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of U.S. ProvisionalPatent Application No. 61/094,802, filed on Sep. 5, 2008, the entirecontent of which is incorporated herein by reference.

BACKGROUND

1. Field of the Invention

The present invention relates to an evaporator and a fuel reformerincluding the same.

2. Discussion of Related Art

A fuel reformer is an apparatus which reforms fuel and generateshydrogen rich gas. This fuel reformer can be used with a fuel cell(which is a clean power generating apparatus that can directly generateelectric energy by an electrochemical reaction of hydrogen and oxygen),etc.

The fuel reformer generally includes a heat source and a reformingreactor. The heat source supplies necessary heat to the reformingreactor, and the reforming reactor reforms fuel and generates hydrogenrich gas. The reforming reactor can generate the hydrogen rich gas usinga steam reforming scheme, an auto-thermal reforming scheme, a partialoxidation scheme, or a combination thereof.

Also, the fuel reformer can further include an evaporator to improvefuel efficiency and apparatus performance. In this case, the evaporatorevaporates a liquid-phase fuel flowing into the evaporator from theoutside, and supplies it (that is, a gas-phase fluid evaporated from theliquid-phase fuel) to the reforming reactor.

That is, when a liquid-phase fuel or water flows into the reformingreactor using the steam reforming scheme, the performance of the fuelreformer is significantly reduced due to an uneven reforming reaction.In order to reduce or prevent this problem, the evaporator may include arelatively long channel as compared to the volume of the fuel reformerso as to evaporate the liquid-phase fuel and/or water flowing in fromthe outside.

Therefore, the evaporator has a large volume due to the long channelstructure. In the case that the evaporator has a small volume, theevaporator has a complicated structure due to a long multi-foldedchannel, such that it is difficult to manufacture. It is thereforedesirable to develop a structure for an evaporator capable of beingsmall and easy to manufacture, and providing a fuel reformer with ahigh-efficiency.

SUMMARY OF THE INVENTION

An aspect of an embodiment of the present invention is directed towardan evaporator capable of having a large output performance, despitehaving a small volume.

Another aspect of an embodiment of the present invention is directedtoward a fuel reformer having the evaporator capable of having the largeoutput performance, despite having the small volume.

An embodiment of the present invention provides an evaporator of a fuelreformer. The evaporator includes a first stage, a second stage, a firstfin structure, and a second fin structure. The first stage has a firstchamber, a first first opening and a first second opening. The firstfirst opening and the first second opening are for allowing the firstfluid to enter into and exit from the first chamber. The second stage isstacked together with the first stage as a stack of the stages, and hasa second chamber, a second first opening and a second second opening.The second first opening and the second second opening are for allowingthe second fluid to enter into and exit from the second chamber. Thefirst fin structure is in the first chamber and for increasing aheat-exchange surface area with a flow of the first fluid within thefirst chamber, and the second fin structure is in the second chamber andfor increasing a heat-exchange surface area with a flow of the secondfluid within the second chamber.

In one embodiment of the evaporator, the first fin structuresubstantially contacts inner surfaces of the first chamber, and/or thesecond fin structure substantially contacts inner surfaces of the secondchamber.

In one embodiment of the evaporator, the first fin structure isconfigured to form turbulence in the flow of the first fluid within thefirst chamber, and the second fin structure is configured to formturbulence in the flow of the second fluid within the second chamber.

In one embodiment, the evaporator further includes a third stage, afirst pipe, and a third fin structure. The third stage has a thirdchamber, a third first opening and a third second opening. The thirdfirst opening and the third second opening are for allowing the firstfluid to enter into and exit from the third chamber, the first pipe ispenetrated through the second stage and for coupling the first chamberto the third chamber, and the third fin structure is in the thirdchamber and for increasing a heat-exchange surface area with a flow ofthe first fluid within the third chamber. Here, the first fin structuresubstantially may contact inner surfaces of the first chamber, thesecond fin structure may substantially contact inner surfaces of thesecond chamber, and the third fin structure may substantially contactinner surfaces of the third chamber. The first pipe may have a first endat the first first opening and a second end at the third second opening.

In addition, the evaporator may further include a fourth stage having afourth chamber, a fourth first opening and a fourth second opening, thefourth first opening and the fourth second opening for allowing thesecond fluid to enter into and exit from the fourth chamber; a secondpipe penetrating through the third stage and for coupling the secondchamber to the fourth chamber; and a fourth fin structure in the fourthchamber and for increasing a heat-exchange surface area with a flow ofthe second fluid within the fourth chamber. Here, the first finstructure may substantially contact inner surfaces of the first chamber,the second fin structure may substantially contact inner surfaces of thesecond chamber, the third fin structure may substantially contact innersurfaces of the third chamber, and the fourth fin structure maysubstantially contact inner surfaces of the fourth chamber. The firstpipe may have a first end at the first first opening and a second end atthe third second opening, and the second pipe may have a first end atthe second second opening and a second end at the fourth first opening.The first fluid may include exhaust gas from a heat source, and thesecond fluid may include at least one of fuel or water. Each of thefirst, second, third and fourth fin structures may include a pluralityof first fins in a first wave pattern having a first wavelength periodand extending in a first direction; and a plurality of second fins in asecond wave pattern substantially identical to the first wave patternand extending alternatively and crisscross between adjacent ones of thefirst fins by a second wavelength period offset from the firstwavelength period by a half wavelength period. Each of the first,second, third and fourth fin structures may be metallic. The fourth finstructure and the second fin structure may be configured to change thesecond fluid from a liquid-phase into a gas-phase by heat energytransferred from the third fin structure and the first fin structure tothe fourth fin structure and the second fin structure.

Another embodiment of the present invention provides an evaporator of afuel reformer. The evaporator includes a first stage, a first finstructure, a second stage, a second fin structure, a third stage, athird fin structure, a first pipe, a fourth stage, a fourth finstructure, and a second pipe. The first stage has a first inlet forallowing a first fluid to enter into the first stage and a first outletfor allowing the first fluid to exit from the first stage. The first finstructure is in the first stage. The second stage has a second inlet forallowing a second fluid to enter into the second stage and a secondoutlet for allowing the second fluid to exit from the second stage. Thesecond fin structure is in the second stage. The third stage has a thirdinlet for allowing the first fluid to enter into the third stage and athird outlet for allowing the first fluid to exit from the third stage,the second stage being between the first stage and the third stage. Thethird fin structure is in the third stage. The first pipe is penetratedthrough the second stage and for coupling the first stage to the thirdstage. The fourth stage has a fourth inlet for allowing the second fluidto enter into the fourth stage and a fourth outlet for allowing thesecond fluid to exit from the fourth stage. The fourth fin structure isin the fourth stage, and the second pipe is penetrated through the thirdstage and for coupling the second stage to the fourth stage.

In one embodiment of the evaporator, the first fin structuresubstantially contacts inner surfaces of the first stage, the second finstructure substantially contacts inner surfaces of the second stage, thethird fin structure substantially contacts inner surfaces of the thirdstage, and the fourth fin structure substantially contacts innersurfaces of the fourth stage.

In one embodiment of the evaporator, the first stage, the second stage,the third stage, and the fourth stage are stacked together as a stack ofthe stages.

In one embodiment, the evaporator is a four-stage evaporator.

In one embodiment of the evaporator, the second fin structure has afirst through-hole penetrated by the first pipe, the third fin structurehas a second through-hole penetrated by the second pipe, and the fourthfin structure has a third through-hole penetrated by a third pipe forsupplying the first fluid from a heat source to the third stage.

In one embodiment, the evaporator further includes a third pipe forsupplying the first fluid from a heat source to the third stage, and afourth pipe for supplying the second fluid in gas-phase to a reformingreactor. Here, the first pipe may have a first end at the first inletand a second end at the third outlet, the second pipe may have a firstend at the second outlet and a second end at the fourth inlet, the thirdpipe may have a first end at the third inlet and a second end at theheat source, and the fourth pipe may a first end at the fourth outletand a second end at the reforming reactor.

In addition, the evaporator may have a plurality of first pipes, and/ora plurality of fourth pipes. The second fin structure may have aplurality of through-holes respectively penetrated by the plurality offirst pipes, the third fin structure may have a second through-holepenetrated by the second pipe, and the fourth fin structure may have athird through-hole penetrated by a third pipe for supplying the firstfluid from a heat source to the third stage.

In one embodiment of the evaporator, the first fluid includes exhaustgas from a heat source, and the second fluid includes at least one offuel or water.

In one embodiment of the evaporator, each of the first, second, thirdand fourth fin structures includes a plurality of first fins in a firstwave pattern having a first wavelength period and extending in a firstdirection, and a plurality of second fins in a second wave patternidentical to the first wave pattern and extending alternatively andcrisscross between adjacent ones of the first fins by a secondwavelength period offset from the first wavelength period by a halfwavelength period.

In one embodiment of the evaporator, each of the first, second, thirdand fourth fin structures is metallic.

In one embodiment of the evaporator, the fourth fin structure and thesecond fin structure are configured to change the second fluid from aliquid-phase into a gas-phase by heat energy transferred from the thirdfin structure and the first fin structure to the fourth fin structureand the second fin structure.

Another embodiment of the present invention provides a fuel reformer.The fuel reformer includes a reforming reactor, an evaporator, and aheat source. The evaporator is for providing a second fluid to thereforming reactor. The heat source is for providing a first fluid to theevaporator. The evaporator includes a first stage having a first inletfor allowing the first fluid to enter into the first stage and a firstoutlet for allowing the first fluid to exit from the first stage; afirst fin structure in the first stage; a second stage stacked togetherwith the first stage as a stack of the stages and having a second inletfor allowing the second fluid to enter into the second stage and asecond outlet for allowing the second fluid to exit from the secondstage; and a second fin structure in the second stage.

In one embodiment of the reformer, the heat source is surrounded by thereforming reactor and is configured to supply heat to the reformingreactor, the first fluid includes exhaust gas from the heat source, andthe second fluid includes at least one of fuel or water.

In one embodiment, the reformer further includes a first pipe having afirst end at the evaporator and a second end at the heat source, and asecond pipe having a first end at the evaporator and a second end at thereforming reactor.

In one embodiment, the reformer further includes a carbon monoxideremover for receiving a reformed fuel from the reforming reactor.

In one embodiment of the reformer, the evaporator further includes athird stage having a third inlet for allowing the first fluid to enterinto the third stage and a third outlet for allowing the first fluid toexit from the third stage, the second stage being between the firststage and the third stage; a third fin structure in the third stage; afirst pipe penetrating through the second stage and for coupling thefirst stage to the third stage; a fourth stage having a fourth inlet forallowing the second fluid to enter into the fourth stage, and a fourthoutlet for allowing the second fluid to exit from the fourth stage; afourth fin structure in the fourth stage; and a second pipe penetratingthrough the third stage for coupling the second stage to the fourthstage. Here, the fuel reformer may further include a third pipe forsupplying the first fluid from the heat source to the third stage, and afourth pipe for supplying the second fluid in gas-phase to the reformingreactor.

In one embodiment of the reformer, the first fin structure substantiallycontacts inner surfaces of the first stage, and the second fin structuresubstantially contacts inner surfaces of the second stage.

A more complete understanding the evaporator and the fuel reformerhaving the same will be afforded to those skilled in the art, by aconsideration of the following detailed description. Reference will bemade to the appended sheets of drawings, which will first be describedbriefly.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, together with the specification, illustrateexemplary embodiments of the present invention, and, together with thedescription, serve to explain the principles of the present invention.

FIG. 1 is a schematic cross-sectional view of an evaporator according toan embodiment of the present invention;

FIG. 2 is a schematic perspective view of an evaporator according toanother embodiment of the present invention;

FIG. 3A is a schematic exploded perspective view of the evaporator ofFIG. 2 from which fin structures are omitted;

FIG. 3B is a schematic cross-sectional view of a first cover plate ofFIG. 3A;

FIG. 4 is a schematic perspective view explaining fin structuresprovided in the evaporator of FIG. 2;

FIG. 5 is a schematic perspective view of a fuel reformer according toan embodiment of the present invention;

FIG. 6 is a schematic cross-sectional view illustrating a configurationwhich can be adopted for a body of the fuel reformer of FIG. 5; and

FIG. 7 is a schematic cross-sectional view illustrating anotherconfiguration which can be adopted for a body of the fuel reformer ofFIG. 5.

DETAILED DESCRIPTION

In the following detailed description, only certain exemplaryembodiments of the present invention are shown and described, by way ofillustration. As those skilled in the art would recognize, the inventionmay be embodied in many different forms and should not be construed asbeing limited to the embodiments set forth herein. Also, in the contextof the present application, when an element is referred to as being “on”another element, it can be directly on the another element or beindirectly on the another element with one or more intervening elementsinterposed therebetween. Like reference numerals designate like elementsthroughout the specification.

In the following description, the term, “gas-phase” refers to a state offluid in which molecules freely move due to a distance interval and aweak bonding force therebetween so that the fluid does not have a set(or predetermined) form and volume and tends to fill a container.Gas-phase fluid has smaller density than a liquid-phase or solid-phasefluid, and can easily change its volume due to an increase or decreaseof pressure. Also, the gas-phase fluid can be easily compressed orheat-expanded.

FIG. 1 is a schematic cross-sectional view of an evaporator 100according to an embodiment of the present invention.

Referring to FIG. 1, the evaporator 100 has a four-stage disk structurein which a first disk 110, a second disk 120, a third disk 130 and afourth disk are stacked with each other.

The first disk 110 has a first chamber 112, a first hole 114 tocommunicate fluids through, and a first fin structure 210 filling thefirst chamber 112. The second disk 120 has a second chamber 122, asecond hole 124 to communicate fluids through, and a second finstructure 220 filling the second chamber 122. The third disk 130 has athird chamber 132, a third hole 134 to communicate fluids through, and athird fin structure 230 filling the third chamber 132. The fourth disk140 has a fourth chamber 142, a fourth hole 144 to communicate fluidsthrough, and a fourth fin structure 240 filling the fourth chamber 142.

The third chamber 132 communicates with the first chamber 112 through afirst pipe 150 such that fluids can flow between the third chamber 132and the first chamber 112. The second chamber 122 communicates with thefourth chamber 142 through a second pipe 160 such that fluids can flowbetween the second chamber 122 and the fourth chamber 142. The thirddisk 130 and the first disk 110 respectively have another holes coupledto the two ends of the first pipe 150. The second disk 120 and thefourth disk 140 respectively have another holes coupled to the two endsof the second pipe 160.

A third pipe 170 may be coupled to the third hole 134 of the third disk130. A fourth pipe 180 may be coupled to the fourth hole 144 of thefourth disk 140.

In the present embodiment, the first pipe 150 is provided to penetratethrough the second disk 120, the second pipe 160 is provided topenetrate through the third disk 130, and the third pipe 170 is providedto penetrate through the fourth disk 140. Such a penetration structureis merely an example to reduce the size of (or to miniaturize) theevaporator. For example, each pipe described above may be providedoutside the evaporator, not penetrating through the disks. Furthermore,the third pipe 170 and fourth pipe 140 are installed to protrude in agravity direction (y direction), in consideration of a reformer coupledto the evaporator 100 in the gravity direction.

Each of the first to fourth fin structures 210, 220, 230, and 240 has anincreased heat exchange surface area in a flow of first fluids or secondfluids. The respective fin structures may be formed of a sheet-shapedmetallic member provided with a plurality of fins (or waves). That is,in one embodiment, the respective fin structures have a shape where aplurality of first fins in a first wave pattern extending in onedirection, and a plurality of second fins in the same wave patterndisposed crisscross together with the wave pattern period of the firstfins by a half period are alternately disposed with each other. (SeeFIG. 4.) That is, in one embodiment, each of the first, second, thirdand fourth fin structures 210, 220, 230, and 240 includes a plurality offirst fins in a first wave pattern having a first wavelength period andextending in a first direction, and a plurality of second fins in asecond wave pattern substantially identical to the first wave patternand extending alternatively and crisscross between adjacent ones of thefirst fins by a second wavelength period offset from the firstwavelength period by a half wavelength period. As such, the fluids canbe evenly distributed in the respective fin structures to formturbulence, and perform a high turbulence flow. The heat exchangesurface may thus increase greatly.

The respective fin structures are installed to fill the respectivedisks. That is, in one embodiment, at least one of the first, second,third and fourth fin structures 210, 220, 230, and 240 substantiallycontacts inner surfaces of its respective chamber 112, 122, 132, or 142.In one embodiment, each of the first, second, third and fourth finstructures 210, 220, 230, and 240 substantially contacts inner surfacesof its respective chamber 112, 122, 132, or 142. Therefore, the heatenergy of the first fluid is efficiently transferred to the third disk130 and first disk 110 when the first fluid having heat energy flowsthrough the third disk 130 and first disk 110. The heat energy of thethird disk 130 and first disk 110 is transferred to the second disk 120and fourth disk 140. When the second fluid flows through the second disk120 and fourth disk 140, the second fluid is heated or evaporated by theheat energy of the second disk 120 and fourth disk 140.

Hereinafter, a configuration of an evaporator of an embodiment of thepresent invention will be described in more detail with reference to anillustrative example.

FIG. 2 is a schematic perspective view of an evaporator 300 according toanother embodiment of the present invention. FIG. 3A is a schematicexploded perspective view of the evaporator 300 of FIG. 2 from which finstructures are omitted. FIG. 3B is a schematic cross-sectional viewtaken along the line III-III of a first cover plate of FIG. 3B.

Referring to FIGS. 2 and 3A, the evaporator 300 includes first to fourthcover plates (or stages) 310, 320, 330, and 340, an auxiliary plate 341b, three first pipes 350 a, 350 b, and 350 c, a second pipe 360, andfirst to fourth fin structures. (See 410, 420, 430, and 440 of FIG. 4.)

The first cover plate 310 has a first circumferential wall 311 forming afirst internal space (or chamber) 312 having a first surface that isopened (see FIG. 3B), and a first hole 314 to communicate fluidsthrough. Here, if the first cover plate 310 is a disk (or has asubstantially flat disk shape), the first surface is one of the twocircular surfaces of the disk that are opposed to each other (or is oneof the two circular surfaces at the top and bottom ends of the disk).The first surface of the first cover plate 310 is covered by an uppersurface 321 a of the second cover plate 320.

Similarly, the second cover plate 320 has a second circumferential wallforming a second internal space (or chamber) having a second surfacethat is opened, and a second hole 324 to communicate fluids through. Thesecond surface of the second cover plate 320 is covered by an uppersurface 331 a of the third cover plate 330. The third cover plate 330has a third circumferential wall forming a third internal space (orchamber) having a third surface that is opened, and at least one hole tocommunicate fluids through. The third surface of the third cover plate330 is covered by an upper surface 341 a of the fourth cover plate 340.The fourth cover plate 340 has a fourth circumferential wall forming afourth internal space (or chamber) having a fourth surface that isopened, and at least one hole to communicate fluids through. The fourthsurface of the fourth cover plate 340 is covered by the auxiliary plate341 b.

Edges of the auxiliary plate 341 b and the fourth to first cover plates340, 330, 320, and 310 may be coupled to each other by welding or thelike. According to the configuration described and shown above, theevaporator 300 of the present embodiment may have a four-stage diskconfiguration similar to the configuration of the evaporator as shown inFIG. 1.

Three first pipes 350 a, 350 b, and 350 c penetrate through the secondcover plate 320 to couple the third internal space of the third coverplate 330 to the first internal space 312 of the first cover plate 310such that fluids can be communicated. To this end, ends of therespective first pipes 350 a, 350 b, and 350 c is coupled to the otherthree holes 326 a, 326 b, and 326 c of the second cover plate 320,respectively. The other ends of the respective first pipes 350 a, 350 b,and 350 c are coupled to the other three holes of the third cover plate330, respectively. The coupling of the ends of the respective firstpipes and the second cover plate 320 and/or the coupling of the otherends of the respective first pipes and the third cover plate 330 mayhave a screw coupling structure. In the present embodiment, the threefirst pipes are merely one embodiment, and the present invention is notthereby limited. For example, one, two, or four or more first pipes maybe utilized.

The second pipe 360 penetrates through the third cover plate 330 tocouple the second internal space of the second cover plate 320 to thefourth internal space of the fourth cover plate 340 such that fluids canbe communicated. To this end, one end of the second pipe 360 is coupledto a third hole 334 of the third cover plate 330. The other end of thesecond pipe 360 is coupled to a fourth hole 348 of the fourth coverplate 340. In one embodiment, the coupling between one end of the secondpipe and the third cover plate 330 and/or the coupling between the otherend of the second pipe 360 and the fourth cover plate 340 has a screwcoupling structure.

The auxiliary plate 341 b includes a plurality of holes 344 a, 344 b,and 346. Among these holes 344 a, 344 b, and 346, one hole 346 may becoupled with the third pipe 370 penetrating through the fourth coverplate 340 and guiding the first fluid introduced into the third internalspace of the third cover plate 330. One end of the third pipe 370 iscoupled to another hole 343 of the fourth cover plate 340. The otherholes 344 a and 344 b of the auxiliary plate 341 b may be coupled withtwo fourth pipes 380 a and 380 b for guiding discharge of the secondfluid, respectively. In the present embodiment, two fourth pipes aremerely one embodiment, and the present invention is not thereby limited.For example, one or three or more pipes may be utilized.

In more detail, the evaporator 300 includes the first cover plate (orstage) 310, the second cover plate (or stage) 320, the third cover plate(or stage) 330, and the fourth cover plate (or stage) 340. The firststage 310 has a first inlet for allowing a first fluid to enter into thefirst stage and the first hole (or outlet) 314 for allowing the firstfluid to exit from the first stage 310. The first fin structure (see 410of FIG. 4) is in the chamber 312 of the first stage 310. The secondstage 320 has the second hole (or inlet) 324 for allowing a second fluidto enter into the second stage 320 and a second outlet for allowing thesecond fluid to exit from the second stage 320. The second fin structure(see 420 of FIG. 4) is in the chamber of the second stage 320. The thirdstage 330 has a third inlet for allowing the first fluid to enter intothe third stage 330 and a third outlet for allowing the first fluid toexit from the third stage 330, the second stage 320 being between thefirst stage 310 and the third stage 330. The third fin structure (see430 of FIG. 4) is in the chamber of the third stage 330. The first pipes350 a, 350 b, and 350 c are penetrated through the second stage 320 andfor coupling the first stage 310 to the third stage (330). The fourthstage 340 has a fourth inlet for allowing the second fluid to enter intothe fourth stage and the fourth outlets (or holes) 344 a and 344 b forallowing the second fluid to exit from the fourth stage. The fourth finstructure (see 440 of FIG. 4) is in the chamber of the fourth stage 340,and the second pipe 360 is penetrated through the third stage 330 andfor coupling the second stage 320 to the fourth stage 340.

According to the configuration described above, the first fluid isintroduced into the third internal space (or third chamber) through thethird pipe 370 and the hole 343 of the fourth cover plate (or fourthstage) 340, transfers heat energy to the third fin structure (see 430 ofFIG.) and flows into the first internal space (or first chamber) 312through the first pipes 326 a, 326 b, and 326 c. Then, the first fluidtransfers heat energy to the first fin structure (see 410 of FIG. 4),and is discharged to the outside through the first hole 314 of the firstcover plate (or first stage) 310.

The liquid-phase second fluid is introduced into the second internalspace (or second chamber) through the second hole 324 of the secondcover plate (or second stage) 320, and flows into the fourth internalspace (or fourth chamber) through the second pipe 360 after passingthrough the second fin structure (see 420 of FIG. 4). Then, via thefourth fin structure (see 440 of FIG. 4), the liquid-phase second fluidis discharged to the outside through the holes 344 a and 344 b of theauxiliary plate 341 b and the fourth pipes 380 a and 380 b. Here, theliquid-phase second fluid is evaporated by heat energy transferred fromthe third fin structure and first fin structure to the second finstructure and fourth fin structure.

FIG. 4 is a schematic perspective view explaining fin structuresprovided in the evaporator of FIG. 2.

Referring to FIG. 4, first to fourth fin structures 410, 420, 430, and440 are filed in the respective internal spaces provided in the first tofourth cover plates 310, 320, 330, and 340. Here, the filling of thefirst to fourth fin structures 410, 420, 430, and 440 refers to theconfiguration in which the fin structures are closely adhered to therespective cover plates, and fins of the respective fin structures aresubstantially evenly distributed in the respective internal spaces. Thatis, in one embodiment, the first fin structure 410 substantiallycontacts inner surfaces of the cover plate (or first stage) 310, thesecond fin structure 420 substantially contacts inner surfaces of thesecond cover plate (or second stage) 420, the third fin structure 330substantially contacts inner surfaces of the third cover plate (or thirdstage) 430, and/or the fourth fin structure 440 substantially contactsinner surfaces of the fourth cover plate (or fourth stage) 340. Thesecond fin structure 420 may have three holes 422 a, 422 b, and 422 cthrough which three first pipes penetrate. The third fin structure 430may have a hole 432 through which the second pipe penetrates. The fourthfin structure 440 may have a hole through which the third pipepenetrates.

The fin structures of the present embodiment have substantially the samestructure. A portion of the fourth fin structure 440 is enlarged inorder to more specifically explain the configuration of the finstructures.

Referring to the enlarged portion, the fourth fin structure 440 has afirst fin arrangement and a second fin arrangement. The first finarrangement has a plurality of first fins 442 extending in a firstdirection, and the second fin arrangement has a plurality of second fins444 extending alternately and crisscross between the adjacent first pinsby a half period in the first direction. That is, in one embodiment, thefourth fin structure 440 includes the plurality of first fins 442 in afirst wave pattern having a first wavelength period and extending in thefirst direction, and the plurality of second fins 444 in a second wavepattern substantially identical to the first wave pattern and extendingalternatively and crisscross between adjacent ones of the first fins bya second wavelength period offset from the first wavelength period by ahalf wavelength period. Here, the first fin 442 and second fin 444 maybe made of a sheet-shape or stripe-shape member. In addition, the firstfin 442 and second fin 444 may be formed of a material having high heattransfer properties. In the present embodiment, the fourth fin structure440 may be formed not only in a single layer structure of the pluralityof first fins 442 and the plurality of second fins 444, but also in amulti-layer structure where these fins are stacked in plural.

The first to third fin structures 410, 420, and 430 have substantiallythe same structure as the fourth fin structure 440, except for thepresence/absence of holes or the position of holes. The fin structuresin the present embodiment may be manufactured by pressing a single metalplate through a press process and brazing it.

According to the configuration of the evaporator described above, as anactive turbulence flow of fluids passing through the respective finstructures is induced, the fluids can be evenly distributed in therespective fin structures and the internal spaces of the respectiveplates, and thus the heat exchange area between the respective disks isincreased greatly. In other words, each of the disks has a high heattransfer coefficient. The heat exchange efficiency of the evaporator canthus be improved. Furthermore, the evaporator can be made smaller (or beminiaturized).

FIG. 5 is a schematic perspective view of a fuel reformer according toan embodiment of the present invention.

Referring to FIG. 5, the fuel reformer includes the evaporator 300 and acylindrical body 500. The structures and functions of the evaporator 300have already been explained above with reference to FIGS. 2 to 4, and,thus, a detailed description thereof will not be provided again.

Here, in one embodiment, the cylindrical body 500 burns a first fuelsupplied through a first connection pipe 512 to generate heat, suppliesa first fluid having heat energy to the evaporator 300, receives agas-phase second fluid from the evaporator 300, generates a reformate byreforming a second fuel, and discharges the reformate through a secondconnection pipe 514. The first fluid may contain exhaust gas having atemperature between about 300 and about 400° C., and the second fluidmay contain the second fuel and vapor.

In the present embodiment, for convenience of explanation, the secondfuel is supplied to the body 50 through the evaporator 300. However,this is merely an example, and the present invention is not therebylimited. For example, the fuel reformer of the present embodiment may beimplemented in a manner such that the gas-phase second fuel is notintroduced into the evaporator 300 but is supplied directly to the body500. The second fuel includes a hydrocarbon-based material such as LPG,natural gas, methanol, ethanol, or the like.

In the present embodiment, for convenience of illustration, the thirdpipe 370 for transferring the first fluid and the fourth pipes 380 a and380 b for transferring the second fluid are illustrated to be exposedbetween the evaporator 300 and the body 500. However, this is merely anexample, and the present invention is not thereby limited. For example,the fuel reformer of the present embodiment may be implemented such thatthe evaporator 300 is directly coupled to the body 500 by shortening thelength of the pipes so that these pipes are not exposed.

FIG. 6 is a schematic cross-sectional view explaining a configurationwhich can be adopted for a body 500 a of the fuel reformer of FIG. 5.

Referring to FIG. 6, the body 500 a of the fuel reformer includes a heatsource 550 and a reforming reactor 600. The body 550 a has a dualcylindrical structure in which the heat source 550 in the form of afirst cylindrical structure is surrounded by the reforming reactor 600in the form of a second cylindrical structure.

The heat source 550 may include a first cylindrical body 560, anoxidation catalyst 570 provided in an internal space 562 of the firstcylindrical body 560, and an igniter 572. A first opening part 564 isprovided on one side of the first cylindrical body 560, and a secondopening part 566 is provided on the other side thereof. The first fueland air are supplied to the internal space 562 through the first openingpart 564 and are oxidized on a surface of the oxidation catalyst 570.One portion of reaction heat generated at this time is supplied to thereforming reactor 600, and the other portion thereof is dischargedthrough the second opening part 566 together with air. The igniter 572ignites the first fuel supplied to the internal space at the time ofinitial operation of the heat source 550. The second opening part 566may be coupled to one end of the third pipe 370. (See FIG. 5.)

The reforming reactor 600 includes a second cylindrical body 610surrounding the first cylindrical body 560 on the same axis, andreforming catalysts 620 provided in an internal space 612 of the secondcylindrical body 610. The reforming catalysts 620 may includegranule-type catalysts. In this case, the reforming catalysts 620 may beencircled by reticular members 622 to reduce (or prevent scattering) ofthe catalysts. Two third opening parts 614 are provided on one side ofthe second cylindrical body 610, with the first opening part 564therebetween, and the fourth opening part 616 is provided on the otherside of the second cylindrical body 610.

The steam supplied from the evaporator 300 of the present embodiment andthe gas-phase second fuel supplied through the evaporator 300 or anotherpipe are supplied to the internal space 612 through the third openingpart 614, wherein the second fuel is subject to the reforming reactionby heat from the heat source 550, passing through the catalysts 620. Thereformate generated by the reforming reaction is discharged through thefourth opening part 616. Here, the reforming reaction may be implementedto include reforming reaction by steam reforming, auto thermal reformingand/or partial oxidation.

FIG. 7 is a schematic cross-sectional view explaining anotherconfiguration which can be adopted for a body 500 b of the fuel reformerof FIG. 5.

Referring to FIG. 7, the body 500 b of the fuel reformer includes a heatsource 650, a reforming reactor 700 and a carbon monoxide remover 750.The body 500 b has a triple cylindrical structure in which the heatsource 650 in the form of a first cylindrical structure is surrounded bythe reforming reactor 700 in the form of a second cylindrical structureon the same axis, and the reforming reactor 700 in the form of a secondcylindrical structure is surrounded by the carbon monoxide remover 750in the form of a third cylindrical structure on the same axis.

The heat source 650 includes a first cylindrical body 660 and a burner670 for emitting flame to an internal space 562 of the first cylindricalbody 660. A first opening part 664 is provided on one side of the firstcylindrical body 660, and a second opening part 666 is provided on theother side thereof. Air is supplied to the internal space 662 throughthe first opening part 664. A portion of heat energy generated by flamesof the burner 670 is supplied to the reforming reactor 700 and thecarbon monoxide remover 750, and another portion of heat energy isdischarged through the second opening part 666 together with air. Thesecond opening part 666 may be coupled to one end of a third pipe 370(See FIG. 5).

The reforming reactor 700 includes a second cylindrical body 710surrounding the first cylindrical body 660 on the same axis, andreforming catalysts 720 provided in an internal space 712 of the secondcylindrical body 710. The reforming catalysts 720 may have a support ina honeycomb or spiral structure and catalyst layers 722 coated on thesupports. Two third opening parts 714 are provided on one side of thesecond cylindrical body 710. The third opening parts 714 may berespectively coupled to one end of the fourth pipes 380 a and 380 b (SeeFIG. 5).

The carbon monoxide remover 750 includes a third cylindrical body 760surrounding the first cylindrical body 660 and the second cylindricalbody 710 on the same axis, and catalysts 770 provided in an internalspace 762 of the third cylindrical body 760. The catalysts 770 mayinclude shift catalysts and/or PROX catalysts. The shift catalystremoves carbon monoxide contained in the reformate through lowtemperature and/or high temperature water gas shift reaction. The PROXcatalyst removes carbon monoxide contained in the reformate through apreferential CO oxidation reaction.

The internal space 762 of the third cylindrical body 710 is coupled tothe internal space 712 of the second cylindrical body 710 through aconnection passage 764 such that they can communicate fluids with eachother. A fourth opening part 766 is provided on one side of the thirdcylindrical body 710. The reformate from which carbon monoxide isremoved is discharged from the internal space 762 to the outside throughthe fourth opening part 766.

The steam supplied from the evaporator 300 of the present embodiment andthe gas-phase second fuel supplied through the evaporator 300 or anotherpipe are supplied to the internal space 712 of the reforming reactor 700through the third opening part 714, wherein the second fuel is reformedby heat from the heat source 650, while passing through the catalysts720. Then, the reformate generated by the reforming reaction flows intothe internal space 762 of the carbon monoxide remover 750 through theconnection passage 764, and a portion of carbon monoxide is removedtherefrom by the catalysts 770. The reformate in which a portion ofcarbon monoxide has been removed is discharged to the outside throughthe fourth opening part 766.

In the present embodiment, for convenience of explanation, the fuelreformer having a body with a cylindrical structure is described.However, this is merely an example, and the present invention is notthereby limited. For example, the fuel reformer according to anembodiment of the present invention may be implemented to have diversekinds and forms of body that can still be utilized with the evaporators100 and 300.

As described above, in the evaporator used in the fuel reformer of anembodiment of the present invention, exhaust gas flowing into the thirdand first chambers of the third and first disks and a second fluid(e.g., water) flowing into the second and fourth chambers of the secondand fourth disks are evenly distributed to increase the heat exchangesurface area between the exhaust gas and the fluid, making it possibleto enhance the heat transfer efficiency. Also, the pulsation (or flowrate difference) of the reformate generated is maintained below about±0.2 L/min by the more efficient evaporation of the second fluid. Suchvalue is considerably small as compared with about ±0.65 L/min of aprior fuel reformer, indicating that a more even flow rate of thereformate can be generated in the fuel reformer.

With an embodiment of the present invention, the output can be improved,while reducing the volume of an evaporator. In particular, a pluralityof disks for performing the heat exchange with each other are crossed,and fin structures are installed in the respective disks, and thus anarea (surface area) contacting fluids within the respective disks canincrease without increasing back pressure, thereby making it possible toenhance the heat exchange efficiency, to increase the vaporizationamount of fluid, and/or to vaporize fluid in a uniform manner. Also, theevaporator has a simple structure, so it can be manufactured with easeand can be mass produced. Furthermore, the pulsation of the reformingreaction in the fuel reformer having the evaporator is maintained to below, thereby making it possible to enhance the performance stability andreliability of the reformer. Also, the fuel reformer having theevaporator can be made small (or be miniaturized), and the warm-up timeof the fuel reformer can be shortened.

To put it another way, a conventional evaporator has a large volume withmultiple stages (e.g., eight stages) to evaporate a liquid-phase fluidinto a gas-phase fluid. However, the large evaporator increases theoverall size of the reformer and the time required to warm-up theevaporator.

By contrast, in view of the foregoing, an embodiment of the presentinvention provides an evaporator having an internal fin structure toincrease a heat-exchange surface area of the evaporator with a flow offluid passing through the internal fin structure. In one embodiment, theevaporator is a four-stage evaporator having first, second, third, andfourth stages, in which each of the stages contains a fin structure. Thefourth and second stages are coupled to each other by a second pipepenetrating through the third stage, and the third and first stages arecoupled to each other by a first pipe penetrating through the secondstage. The fin structures of the fourth and second stages are configuredto evaporate a fuel and water from a liquid-phase into a gas-phase byheat energy transferred from the fins of the first and third stages.Here, the heat energy of the first and third stages is derived from anexhaust gas from a heater, the exhaust gas passing through the finstructures of the first and third stages. As such, the fin structures ofthe first, second, third, and fourth stages increase the heat exchangesurface area between the exhaust gas and the fuel and water to enhanceheat transfer efficiency, while not increasing the overall size of theevaporator.

While the present invention has been described in connection withcertain exemplary embodiments, it is to be understood that the inventionis not limited to the disclosed embodiments, but, on the contrary, isintended to cover various modifications and equivalent arrangementsincluded within the spirit and scope of the appended claims, andequivalents thereof.

What is claimed is:
 1. An evaporator of a fuel reformer comprising: afirst stage having a first chamber, a first first opening and a firstsecond opening, the first first opening and the first second opening forallowing a first fluid to enter into and exit from the first chamber; asecond stage stacked together with the first stage as a stack of thestages, the second stage having a second chamber, a second first openingand a second second opening, the second first opening and the secondsecond opening for allowing a second fluid to enter into and exit fromthe second chamber; a first fin structure in the first chamber and forincreasing a heat-exchange surface area with a flow of the first fluidwithin the first chamber; and a second fin structure in the secondchamber and for increasing a heat-exchange surface area with a flow ofthe second fluid within the second chamber, wherein each of the firstand the second fin structures comprises: a plurality of first fins eachextending along a first direction in a first wave pattern having a firstperiod; and a plurality of corresponding second fins each extendingalong the first direction in a second wave pattern having the firstperiod and being offset from the first wave pattern by one half of thefirst period, the second fins being arranged alternately with thecorresponding first fins, wherein the first fin structure substantiallycontacts inner surfaces of the first chamber, wherein the second finstructure substantially contacts inner surfaces of the second chamber.2. The evaporator of claim 1, wherein: the first fin structure isconfigured to form turbulence in the flow of the first fluid within thefirst chamber, and the second fin structure is configured to formturbulence in the flow of the second fluid within the second chamber. 3.The evaporator of claim 1, further comprising: a third stage having athird chamber, a third first opening and a third second opening, thethird first opening and the third second opening for allowing the firstfluid to enter into and exit from the third chamber; a first pipepenetrating through the second stage and for coupling the first chamberto the third chamber; and a third fin structure in the third chamber andfor increasing a heat-exchange surface area with a flow of the firstfluid within the third chamber.
 4. The evaporator of claim 3, wherein:the first fin structure substantially contacts inner surfaces of thefirst chamber, the second fin structure substantially contacts innersurfaces of the second chamber, and the third fin structuresubstantially contacts inner surfaces of the third chamber.
 5. Theevaporator of claim 3, wherein the first pipe has a first end at thefirst first opening and a second end at the third second opening.
 6. Theevaporator of claim 3, further comprising a fourth stage having a fourthchamber, a fourth first opening and a fourth second opening, the fourthfirst opening and the fourth second opening for allowing the secondfluid to enter into and exit from the fourth chamber; a second pipepenetrating through the third stage and for coupling the second chamberto the fourth chamber; and a fourth fin structure in the fourth chamberand for increasing a heat-exchange surface area with a flow of thesecond fluid within the fourth chamber.
 7. The evaporator of claim 6,wherein: the first fin structure substantially contacts inner surfacesof the first chamber, the second fin structure substantially contactsinner surfaces of the second chamber, the third fin structuresubstantially contacts inner surfaces of the third chamber, and thefourth fin structure substantially contacts inner surfaces of the fourthchamber.
 8. The evaporator of claim 6, wherein: the first pipe has afirst end at the first first opening and a second end at the thirdsecond opening, and the second pipe has a first end at the second secondopening and a second end at the fourth first opening.
 9. The evaporatorof claim 8, wherein: the first fluid comprises exhaust gas from a heatsource, and the second fluid comprises at least one of fuel or water.10. The evaporator of claim 6, wherein each of the third and fourth finstructures comprises: corresponding first fins each extending along thefirst direction in the first wave pattern having the first period; andcorresponding second fins each extending along the first direction inthe second wave pattern having the first period and being offset fromthe first wave pattern by one half of the first period, the second finsbeing arranged alternately with the corresponding first fins.
 11. Theevaporator of claim 10, wherein the first, second, third, and fourth finstructures are substantially evenly distributed in respective internalspaces of the first, second, third, and fourth chambers.
 12. Theevaporator of claim 6, wherein each of the first, second, third andfourth fin structures comprises metallic sheets each having alternatingpeaks and valleys arranged in the first wave pattern or the second wavepattern.
 13. The evaporator of claim 6, wherein the fourth fin structureand the second fin structure are configured to change the second fluidfrom a liquid-phase into a gas-phase by heat energy transferred from thethird fin structure and the first fin structure to the fourth finstructure and the second fin structure.
 14. The evaporator of claim 6,further comprising an auxiliary plate, wherein the first stagecomprises: a first peripheral wall; and a first cover plate coupled to atop surface of the first peripheral wall, wherein the second stagecomprises: a second peripheral wall; and a second cover plate coupled toa top surface of the second peripheral wall, wherein the third stagecomprises: a third peripheral wall; and a third cover plate coupled to atop surface of the third peripheral wall, wherein the fourth stagecomprises a fourth peripheral wall; and a fourth cover plate coupled toa top surface of the fourth peripheral wall, and wherein the fourthstage is stacked on the auxiliary plate to form the fourth chamber, thethird stage is stacked on the fourth stage to form the third chamber,the second stage is stacked on the third stage to from the secondchamber, and the first stage is stacked on the second stage to from thefirst chamber.
 15. The evaporator of claim 14, wherein the first,second, third, fourth, and auxiliary cover plates have a substantiallyflat disk shape, and wherein the first, second, third, and fourth stagesstack together in a substantially cylindrical shape.
 16. An evaporatorof a fuel reformer comprising: a first stage having a first inlet forallowing a first fluid to enter into the first stage and a first outletfor allowing the first fluid to exit from the first stage; a first fanstructure in the first stage; a second stage having a second inlet forallowing a second fluid to enter into the second stage and a secondoutlet for allowing the second fluid to exit from the second stage; asecond fin structure in the second stage; a third stage having a thirdinlet for allowing the first fluid to enter into the third stage and athird outlet for allowing the first fluid to exit from the third stage,the second stage being between the first stage and the third stage; athird fin structure in the third stage; a first pipe penetrating throughthe second stage and for coupling the first stage to the third stage; afourth stage having a fourth inlet for allowing the second fluid toenter into the fourth stage and a fourth outlet for allowing the secondfluid to exit from the fourth stage, a fourth fin structure in thefourth stage; and a second pipe penetrating through the third stage andfor coupling the second stage to the fourth stage, wherein each of thefirst, second, third and fourth fin structures comprises: a plurality offirst fins each extending along a first direction in a first wavepattern having a first period; and a plurality of corresponding secondfins each extending along the first direction in a second wave patternhaving the first period and being offset from the first wave pattern byone half of the first period, the second fins being arranged alternatelywith the corresponding first fins, wherein the first fin structuresubstantially contacts inner surfaces of the first stage, wherein thesecond fin structure substantially contacts inner surfaces of the secondstage, wherein the third fin structure substantially contacts innersurfaces of the third stage, wherein the fourth fin structuresubstantially contacts inner surfaces of the fourth stage.
 17. Theevaporator of claim 16, wherein the first stage, the second stage, thethird stage, and the fourth stage are stacked together as a stack of thestages.
 18. The evaporator of claim 16, wherein the evaporator comprisesa four-stage evaporator.
 19. The evaporator of claim 16, wherein: thesecond fin structure has a first through-hole penetrated by the firstpipe; the third fin structure has a second through-hole penetrated bythe second pipe; and the fourth fin structure has a third through-holepenetrated by a third pipe for supplying the first fluid from a heatsource to the third stage.
 20. The evaporator of claim 16, furthercomprising: a third pipe for supplying the first fluid from a heatsource to the third stage; and a fourth pipe for supplying the secondfluid in gas-phase to a reforming reactor.
 21. The evaporator of claim20, wherein: the first pipe has a first end at the first inlet and asecond end at the third outlet, the second pipe has a first end at thesecond outlet and a second end at the fourth inlet, the third pipe has afirst end at the third inlet and a second end at the heat source, andthe fourth pipe has a first end at the fourth outlet and a second end atthe reforming reactor.
 22. The evaporator of claim 21, wherein the firstpipe comprises a plurality of first pipes.
 23. The evaporator of claim22, wherein the fourth pipe comprises a plurality of fourth pipes. 24.The evaporator of claim 23, wherein: the second fin structure has aplurality of through-holes respectively penetrated by the plurality offirst pipes; the third fin structure has a second through-holepenetrated by the second pipe; and the fourth fin structure has a thirdthrough-hole penetrated by a third pipe for supplying the first fluidfrom a heat source to the third stage.
 25. The evaporator of claim 16,wherein: the first fluid comprises exhaust gas from a heat source, andthe second fluid comprises at least one of fuel or water.
 26. Theevaporator of claim 16, wherein each of the first, second, third andfourth fin structures comprises metallic sheets each having alternatingpeaks and valleys arranged in the first wave pattern or the second wavepattern.
 27. The evaporator of claim 16, wherein the fourth finstructure and the second fin structure are configured to change thesecond fluid from a liquid-phase into a gas-phase by heat energytransferred from the third fin structure and the first fin structure tothe fourth fin structure and the second fin structure.